1. Field of the Invention
Exemplary embodiments of the present invention relate to a metal wiring etchant and a method for manufacturing metal wiring using the same.
2. Discussion of the Background
A thin film transistor (TFT) array panel may be used as a circuit board for independently driving pixels in a liquid crystal display or an organic electro-luminescent (EL) display device.
The thin film transistor array panel may include a scanning signal line or a gate line for transmitting a scanning signal, an image signal line or a data line for transmitting an image signal, a thin film transistor connected to the gate line and the data line, and a pixel electrode connected to the thin film transistor.
The thin film transistor may include a gate electrode that is a portion of the gate wire, a semiconductor layer forming a channel, a source electrode that is a portion of the data wire, and a drain electrode.
The thin film transistor is a switching element that controls an image signal transmitted to the pixel electrode through the data wire according to the scanning signal transmitted through the gate line.
To manufacture the thin film transistor, a metal layer as a wiring material for a gate electrode or a source/drain electrode pair is deposited on a substrate, and the metal layer is etched by using a corrosive gas or a solvent to realize a desired path of the electrical circuit.
While downsizing and highly integrating the circuit, the metal wire becomes thin, however electrical resistance is relatively increased.
Accordingly, copper is increasingly gaining attention as the wiring material having low resistance instead of chromium, molybdenum, aluminum, and alloys mainly used as the conventional wiring material.
However, copper may have poor adherence with a glass substrate or a silicon insulating layer such that it is difficult to use a single layer of copper, and thereby a titanium layer having excellent adherence with the glass substrate or the silicon insulating layer may be used as a lower layer in a multilayer with copper.
To etch this multilayer, a peroxide-based etchant is used, but if the peroxide-based etchant includes metal ions at more than a predetermined concentration, peroxide decomposition is accelerated and it is quickly decomposed into water and oxygen such that heat and quick composition change may be generated, thereby generating instability.
To solve this problem of hydrogen peroxide decomposition, a peroxide solution stabilizer may be added, however the addition of the expensive stabilizer increases the cost.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form any part of the prior art.